Analog meters used in power industries are simple to install, use, and have low manufacturing costs but have many limitations that include shock, wear, magnetic sensitivity, unreliability, and fragility. In addition, analog meters tend to have stuck needles, and suffer from inaccurate measurements, and erroneous readings by operators.
Various attempts have been made to address the limitations of the analog meters. One example approach is shown by Fest et. al. in U.S. Pat. No. 9,054,725. Therein, meters having digital asset componentry or microcontroller is shown. The microcontroller measures an input signal from an input current loop and transmits an output signal to a desired output current loop, without requiring external power other than the one already existing in the current loop. In addition, the microcontroller reports instrument status and loss of signal to eliminate operator error in assuming the meter is faulty when in actuality a loss of signal has occurred. However, the controllers are targets for criminal hacking. Hence, there is a need, particularly in the nuclear industry, for a digital meter that is compliant with cyber security requirements.